Adjustable tool holder

ABSTRACT

An adjustable tool holder, for use in a machine tool, such as a lathe, for holding a tool, such as a cutter, by means of which a workpiece is to be machined, comprises a body fixable on the machine tool and a bridge, adapted for the tool, such as the cutter to be secured thereto, said bridge (a) locating, at one end on one or more spherical elements which engage in the body and provide a swivel axis for the bridge, and (b) being connected at the other end to the body by an adjusting screw rotation of which adjusts the proximity of the bridge relative to the body by swinging it about the swivel axis, and therefore provides fine adjustment of the tool.

United States Patent 1191 Andersson July 24, 1973 ADJUSTABLE TOOL HOLDER2,527,871 10/1950 Bakewell 29/975 R x t l I [76] or g3 i g zg gzgg iPrimary Examiner-l-1arr1son L. l-linson Attorney-George Vande Sande [22]Filed: Feb. 23, 1972 21 Appl. 110.; 228,591 [571 ABSTRACT An adjustabletool holder, for use in a machine tool, such as a lathe, for holding atool, such as a cutter, by [52] 11.8. CI. 29/97.5 R, 82/36 R means ofwhich a workpiece is to be machined [55 ntidCl. B2611 1/00, B23b 29/00prises a body fixable on the machine tool and a bridge, [5 of Search291975 82/36 R adapted for the tool, such as the cutter to be securedthereto, said bridge (a) locating, at one end on one or [56] ReferencesCited more spherical elements which engage in the body and UNITED STATESPATENTS provide a swivel axis for the bridge, and (b) being con-3,557,646 1/1971 Agnew 29/97.5 R nected at the other end to the body byan adjusting 3,543,618 12/1970 Holden 82/36 R screw rotation of whichadjusts the proximity of the 3,232,153 2/1966 Davis 29/975 R relative tothe winging it about the 2,962,800 12/1960 Swanson 29/975 R X swivelaxis, and therefore provides fine adjustment of 2,928,906 3/1960 Gernert29/97.5 R X the too] 2,916,802 12/1959 Blandstand 29/975 R 2,597,6195/1952 Clark 29/975 R X 16 Claims, 12 Drawing Figures PATENTEU JUL24|9753, 747, 180

sum u or 4 I 1 ADJUSTABLE TOOL HOLDER This invention relates to anadjustable tool holder for use in a machine tool, such as a lathe, forholding a tool, such as a cutter tool, by means of which a workpiece isto be machined.

In this field, improvements in precision are continually striven for,since certain workpieces can never be machined sufficiently precisely.At the same time, efforts are being made to improve rapid adjustment andcontrol of the exact position of the tool in relation to the workpiece.Such position adjustments have to be effected comparatively frequently,not only before starting work, but also during the work, sinceinevitable temperature variations always cause changes of the relativepositions of the tool and the workpiece.

Solutions hitherto proposed on the basis of the above-mentionedaspirations can be considered only as compromise solutions as none ofthem satisfy simultaneously both the need for machining precision andthe need for rapidity of adjustment. An object of the present inventionis to provide an adjustable tool holder which simultaneously fulfilsboth these needs.

With this object in view, the present invention provides a tool holder,for a tool such as a cutting tool for a lathe comprising a fixable bodyhaving means for securing a tool thereto with coarse adjustment,characterised in that the said means for securing is provided on abridge which butts by one end against said body by way of at least onespherical element which provides a swivel axis for limited swinging ofsaid bridge, the other end of said bridge being swingable, by means ofan adjusting screw engaged in said body, in finely adjustable mannerrelative to said body.

The invention will be described further, by way of example, withreference to the accompanying drawings, in which i FIG. 1 is apart-sectional side elevation of a first embodiment of the holder of theinvention;

FIG. 2 is a section taken along the line A-A of FIG.

FIG. 3 shows the same holder as viewed from below in FIG. 1;

FIG. 4 shows the same holder as viewed from the left in FIG. 1;

FIG. 5 shows the same holder as viewed from the left in FIG. 4;

FIG. 6 is a part-sectional side elevation of a second embodiment of thetool holder of the invention;

FIG. 7 is a part-sectional plan view of the holder shown in FIG. 6;

FIG. 8 is a part-sectional end elevation of the same holder as viewedfrom the left in FIG. 6, one of the components having been omitted;

FIG. 9 is a side view of a third embodiment of the holder of theinvention;

FIG. 10 is a part-sectional plan view of the holder shown in FIG. 9;

FIG. 11 is a part-sectional end view of the same holder as viewed fromthe right in FIG. 9; and

FIG. 12 is a section taken on the line 8-8 of FIG. 9.

The tool holder shown in FIGS. 1 to 5 will firstly be described. Thisholder is designated as a whole by the reference numeral 1 and issuitable for mounting on an automatic turning lathe so as to berotatable. Mirrorinverted, the holder can be used in a turret turninglathe. This does not, of course, preclude the possibility that the toolholder can be used in other environments, i.e. in other machine tools.

The holder 1 has a hollow cylindrical shank 2 for clamping, for example,in the turret head of a machine tool. Axial central bore 3 of the shank2 is open at the free end thereof and also extends through a body 4connected to the other end of the shank 2. This body 4 extends in anaxial plane, as can be seen from FIG. 1, somewhat outside the peripheryof the shank 2 to provide an axially-extending locating surface 5, at aright angle to the said plane, for the mounting of a bridge 6 whichlocates by an angle bracket 7 thereof, at a slight spacing, on thissurface 5. This spacing is provided by two spherical elements 8 whichare located in sockets 9 and 10, disposed opposite one anotherrespectively in the locating surface 5 and the angle bracket 7.Respective channels, not shown, may extend freely outwards from thebottoms of the sockets 8, 9.

Disposed preferably between the two spherical elements 8 and extendingthrough the angle bracket 7 is a clamping bolt 11 which extends throughthe locating surface 5 and is anchored in the body 4. This bolt 11 issurrounded, with substantial clearance in the angle bracket 7, by acountersunk bore 12. Arranged between the head of the bolt 11 and theshoulder provided by the countersunk bore 12 is at least one disc springor the like 13 which presses the angle bracket 7 of the bridge 6securely against the spherical elements 8 and, consequently, against thebody 4. Thanks to this disc spring, and the clearance between theclamping bolt 11 and to the shoulder in the bore 12, as well as to thedesign and the co-operative relationship between the bridge 6 and thebody 4 by way of the spherical elements 8, limited swinging movement ofthe bridge 6 relative to the fixed body 4 about an axis extendingthrough the centres of the spherical elements 8 is possible. The bridge6 serves for the reception and holding of a cutting or like too] asindicated in dot-dash lines at 14 in FIG. 4.

The body 4 extends, in the said axial plane, transversely away from thelocating surface 5, in order to form, alongside a corresponding portion16 of the bridge 6, a projection 15 which projects beyond the peripheryof the shank 3 and which serves for connection thereto of the bridgeportion 16 and for securing the latter so as to be at an extremelyfinely adjustable spacing therefrom. For this purpose, an adjusting crew17 extends through the bridge part 16 and is anchored in the projection15. The head of the adjusting screw 17 abuts against a disc 19 whichrests by a spherical surface thereof against a correspondingly formedshoulder in a countersunk bore 18 in the bridge portion 16. The centralsection of the shank of the adjusting screw 17 is surrounded by acomparatively powerful spring 20, which is accommodated in recesses 21and 2 2 in the parts 15 and 16-, and which presses these parts apart, sothat the bridge portion 16 butts securely against the disc 19 and,consequently, against the head of the adjusting screw 17 which head ispreferably graduated as shown in FIG. 5.

The bridge 6 extends axially forwards with a central part 23 which iscantilevered at its free end. The part 23 is shaped to provide twotransverse clamping jaws 24, 25 in which clamping bolts 26, 27 and 28and a cylindrical peg 29 are fitted for the purpose of receiving andsecuring the tool 14, these bolts 26, 27, 28 providing for coarseadjustment of the tool 14 in a transverse plane.

The above-described holder is extremely easy to instal, as well as toadjust coarsely and finely. After clamping the holder in a machine tooland the mounting of the workpiece to be machined, the tool 14 isinitially coarsely adjusted by means of the bolts 26, 27, 28 as willreadily be understood from the drawingsLThen the adjusting screw 17 isrotated until the desired exact positioning of the tool 14, for examplerelative to the workpieces centre, is achieved. Adjustments with anaccuracy of 0.005 mm are possible, whilst the arrangement may providefor total fine adjustment to the amount of 2 mm. The holder is compact,stable and robust, and allows both increase and decrease of the spacingof the tool from the workpieces centre without the slightest play orback-lash. The fine adjustment takes place both extremely accurately andrapidly, and to achieve this only one adjusting screw has to beactuated. Forces arising during machining are absorbed, in the exampleshown, by the outer spherical element 8. Because the adjusting screw 17is positioned far away from the swivel axis formed by the sphericalelements 8 and also from the tool 14, extremely fine precision isachieved.

The second embodiment of the tool holder of the invention shown in FIGS.6, 7 and 8 is indicated by the reference numeral 31 and is adapted foruse both for internal and external turning. It is constructed, inprinciple, similarly to the tool holder of FIGS. 1 to 5, and comprises ashank 32 and a body 34 having a central bore 33, the body 34 having alocating surface 35 and projection 45. All the parts of this embodimentwhich correspond to similar parts of the embodiment of FIGS. 1 to aredesignated by corresponding reference numerals increased by 30.

The primary difference from the embodiment of FIGS. 1 to 5 consists inthat the body 34 is provided with an axial recess 60 which issubstantially concentric to the axis of the shank 32. The bridgeprotrudes into this recess 60 with a corresponding, but smaller,projection 61 having a coaxial contiguous bore 62 which preferably has asomewhat lesser diameter than the bore 33 of the shank 32. Introducedinto the bore 62 is a rod 63 which is locked by screws 64 and 65 andwhose outer end carries a tool 44 fixed by means of a screw 66.Otherwise, this embodiment corresponds to the one described withreference to FIGS. 1 to 5.

Illustrated in FIGS. 9 to 12 is an adjustable tool holder 71 which isintended chiefly for use in relation to boring. The entire holder hasthe overall shape of a substantially hollow cylinder, and comprises abody split by at least one radially and axially extending cut 101 intosides 74a, 74b, which are adapted to be pressed together by bolts 102for the purposes of frictional locking onto a rod (not shown) that is tobe clamped. Of course, the out can be effected diametrically, so thatthe body is in two halves which can be connected together in the mannerdescribed.

Separated from the body, by the said radially and axially extending cut101 as well as by a diametrical continuation 103 of the same and a cut104 extending, preferably obliquely, peripherally of the body, is abridge 76 whose longer axial edge butts against the corresponding edge75 of the body by way of spherical elements 78 between which is aclamping bolt 81 fitted with disc springs or the like 83. The shorteraxial edge 86 of the bridge 76 is connected adjustably to the body by anadjusting screw 87 fitted with a spherical disc 89 and a pressure spring90 accommodated in recesses 91 and 92.

The central part of the bridge 76 is formed with an oblique slot foraccommodating a tool 84 which is directed obliquely forwards andoutwards of the holder and is secured by means of a screw 105.

The function and mode of operation of this embodiment is the same asthat of the two previouslydescribed embodiments.

Of course, modifications can be made to the described embodiments withinthe scope of the invention as defined by the following claims. Thus, forexample, the bridge 7 (FIG. 2) can extend partially around the body andcan butt by way of spherical elements, in the described manner, againstthe body. In this case, a further pressure spring can be insertedbetween the two end regions of the bridge, and the clamping bolt 11 can,possibly, be omitted.

Also, the clamping bolts may be replaced by a clamping element which issubstantially C-shaped in profile, a C-shaped stirrup or yoke, or thelike. Such an element can engage, at a bracing, around the sphericalelements so that the ends of the CS lie in the same plane as one of thecommon planes of symmetry of the spherical elements which plane extends,like the back of the C, approximately parallel to the bridge. The twoends of the CS can also be anchored in the body in such a way that thespherical elements lie completely in the C whose longitudinal plane ofsymmetry is arranged parallel to the bridge.

I claim:

1. An adjustable tool holder, for a tool such as a cutting tool for alathe comprising a fixable body having means for securing a tool theretowith coarse adjustment, characterised in that the said means forsecuring is provided on a bridge which butts by one end against saidbody by way of at least one spherical element which provides a swivelaxis for limited swinging of said bridge, the other end of said bridgebeing swingable, by means of an adjusting screw engaged in said body, infinely adjustable manner relative to said body.

2. A tool holder as set forth in claim 1, characterised in that saidswivel axis of said bridge is provided by at least two of said sphericalelements between which is at least one clamping bolt which is engagedrotatably in said body and is surrounded, with clearance, by a bore insaid bridge.

3. A tool holder as set forth in claim 2, characterised in that saidclamping bolt bore is formed with a shoulder, and at least one discspring is disposed between said shoulder and the head of said clampingbolt.

4. A tool holder as set forth in claim 1, characterised in that saidadjusting screw is surrounded by a pressure spring which permanentlypresses apart the respective ends of said body and said bridge.

5. A tool holder as set forth in claim 4, characterised in that saidadjusting screw is surrounded, with clearance, by a countersunk borewhich is arranged in said bridge and has a shoulder of concave form, andin that a corresponding planoconvex disc butts against said shoulder andagainst the head of said adjusting screw, to permit limited swivelmovement of said bridge relative to said adjusting screw.

6. A tool holder as set forth in claim 1, characterised in that saidadjusting screw is provided with a graduated scale.

7. A tool holder as set forth in claim 1, characterised in that saidbody is hollow in design and is provided with a hollow shank, in thatsaid body projects beyond said shank on two opposed sides of an axialplane, and in that said bridge conforms with the contour of said body inthe region of said adjusting screw, whilst said bridge projects, in theregion of said axis, parallel to said axial plane beyond said body, inorder to butt, by its projecting part, against said body, by way of saidspherical element, by means of an angle bracket.

8. A tool holder as set forth in claim 7,.characterised in that acentral part of said bridge is extended forwards to provide clampingjaws for the locking and coarse adjusting of said tool by means ofclamping bolts.

9. A tool holder as set forth in claim 7, characterised in that saidbody is provided with an axial recess which extends substantiallyconcentrically to the axis of said shank, and in that said bridgeengages into this recess by a corresponding, but smaller-dimensioned,projection having a bore which is coaxial with the shank and of reduceddiameter, for the reception of a rod which supports said tool and whichcan be fixed by means of clamping bolts.

10. A tool holder as set forth in claim 1, characterised in that saidholder has an overall shape approximating to a hollow cylinder which isdivided by cuts to define said body, which is adapted to be secured ontoa rod, said bridge, which is mounted in a limitedly swingablemanner onsaid body and which is separated from said body by axial ones of saidcuts, and a cut which extends in the peripheral direction of saidcylinder.

11. A tool holder as set forth in claim 10, characterised in that saidcut which extends in the peripheral direction extends obliquely in orderto provide, on said bridge, a longer axial edge and a shorter axialedge.

12. A tool holder as set forth in claim 11, characterised in that saidlonger axial edge has therethrough a clamping bolt which extendstangentially through said edge and is engaged rotatably in a confrontingedge of said body whilst said shorter axial edge of said bridge, and therespective confronting edge of said body receive a similarly arrangedadjusting screw.

13. A tool holder as set forth in claim 12, characterised in that acentral section of said bridge supports said tool which is directedobliquely forwards and outwards and is locked, so as to be coarselyadjustable, by means of a clamping bolt.

14. A tool holder as set forth in claim 10, characterised in that saidbody is divided by at least one axial cut, and in that the body sidesformed in this way are held together by tangentially arranged screwswhich clamp the body on a rod.

15. A tool holder as set forth in claim 1, characterised in that saidbridge and said body are held together by a clamping member which isC-shaped in profile and which engages, at a spacing therefrom, aroundsaid spherical elements so that the ends of said C lie in one of thecommon planes of symmetry of said spherical elements which planeextends, like the back of said C, approximately parallel to said bridge.

16. A tool holder as set forth in claim 1, characterised in that saidbridge and said body are held together by a clamping member which isC-shaped in profile and which embraces, at a spacing therefrom, thespherical elements which lie completely in the C whoselongitudinally-extending plane of symmetry is arranged parallel to saidbridge and whose two ends are anchored to said body.

@ 2 3 UNITED STATES PATENT OFFICE CERTIFICATE 0F QO'RRECHON Patent No.74711-80 Dated July .1973

lnventofls) KARL IVAN ANDERSSON It is certified that error apoears inthe above-identified patent and that said Letters Patent are herebycorrected as shown below:

Foreign Application Priority Data March- 5, 1971' Sweden. Q .2892/71Signedgand sealed this 25th day of December 1973.

T -(SEAL) Attest: 1

EDWARD M.FLETCHER,,JR. RENE D. TEGTMEYER Attesting Officer ActingCommissioner of Patents

1. An adjustable tool holder, for a tool such as a cutting tool for alathe comprising a fixable body having means for securing a tool theretowith coarse adjustment, characterised in that the said means forsecuring is provided on a bridge which butts by one end against saidbody by way of at least one spherical element which provides a swivelaxis for limited swinging of said bridge, the other end of said bridgebeing swingable, by means of an adjusting screw engaged in said body, infinely adjustable manner relative to said body.
 2. A tool holder as setforth in claim 1, characterised in that said swivel axis of said bridgeis provided by at least two of said spherical elements between which isat least one clamping bolt which is engaged rotatably in said body andis surrounded, with clearance, by a bore in said bridge.
 3. A toolholder as set forth in claim 2, characterised in that said clamping boltbore is formed with a shoulder, and at least one disc spring is disposedbetween said shoulder and the head of said clamping bolt.
 4. A toolholder as set forth in claim 1, characterised in that said adjustingscrew is surrounded by a pressure spring which permanently presses apartthe respective ends of said body and said bridge.
 5. A tool holder asset forth in claim 4, characterised in that said adjusting screw issurrounded, with clearance, by a countersunk bore which is arranged insaid bridge and has a shoulder of concave form, and in that acorresponding planoconvex disc butts against said shoulder and againstthe head of said adjusting screw, to permit limited swivel movement ofsaid bridge relative to said adjusting screw.
 6. A tool holder as setforth in claim 1, characterised in that said adjusting screw is providedwith a graduated scale.
 7. A tool holder as set forth in claim 1,characterised in that said body is hollow in design and is provided witha hollow shank, in that said body projects beyond said shank on twoopposed sides of an axial plane, and in that said bridge conforms withthe contour of said body in the region of said adjusting screw, whilstsaid bridge projects, in the region of said axis, parallel to said axialplane beyond said body, in order to butt, by its projecting part,against said body, by way of said spherical element, by means of anangle bracket.
 8. A tool holder as set forth in claim 7, characterisedin that a central part of said bridge is extended forwards to provideclamping jaws for the locking and coarse adjusting of said tool by meansof clamping bolts.
 9. A tool holder as set forth in claim 7,characterised in that said body is provided with an axial recess whichextends substantially concentrically to the axis of said shank, and inthat said bridge engages into this recess by a corresponding, butsmaller-dimensioned, projection having a bore which is coaxial with theshank and of reduced diameter, for the reception of a rod which supportssaid tool and which can Be fixed by means of clamping bolts.
 10. A toolholder as set forth in claim 1, characterised in that said holder has anoverall shape approximating to a hollow cylinder which is divided bycuts to define said body, which is adapted to be secured onto a rod,said bridge, which is mounted in a limitedly swingable manner on saidbody and which is separated from said body by axial ones of said cuts,and a cut which extends in the peripheral direction of said cylinder.11. A tool holder as set forth in claim 10, characterised in that saidcut which extends in the peripheral direction extends obliquely in orderto provide, on said bridge, a longer axial edge and a shorter axialedge.
 12. A tool holder as set forth in claim 11, characterised in thatsaid longer axial edge has therethrough a clamping bolt which extendstangentially through said edge and is engaged rotatably in a confrontingedge of said body whilst said shorter axial edge of said bridge, and therespective confronting edge of said body receive a similarly arrangedadjusting screw.
 13. A tool holder as set forth in claim 12,characterised in that a central section of said bridge supports saidtool which is directed obliquely forwards and outwards and is locked, soas to be coarsely adjustable, by means of a clamping bolt.
 14. A toolholder as set forth in claim 10, characterised in that said body isdivided by at least one axial cut, and in that the body sides formed inthis way are held together by tangentially arranged screws which clampthe body on a rod.
 15. A tool holder as set forth in claim 1,characterised in that said bridge and said body are held together by aclamping member which is C-shaped in profile and which engages, at aspacing therefrom, around said spherical elements so that the ends ofsaid C lie in one of the common planes of symmetry of said sphericalelements which plane extends, like the back of said C, approximatelyparallel to said bridge.
 16. A tool holder as set forth in claim 1,characterised in that said bridge and said body are held together by aclamping member which is C-shaped in profile and which embraces, at aspacing therefrom, the spherical elements which lie completely in the Cwhose longitudinally-extending plane of symmetry is arranged parallel tosaid bridge and whose two ends are anchored to said body.